Apparatus for drying coated sheet stock



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44 INVENTOR. 5 1 zBKMQS-JC Ranfienul l n x BY 1 WITNESS l E Q 53 162;: A B J 2' W15 ww S mm) United States Patent 3,289,814 APPARATUS FOR DRYING C(BATED SHEET STGCK Thomas J. Rosema, Grand Rapids, Mich, assignor to General Research, Inc., Grand Rapids, Mich a corporation of Michigan Filed Jan. 23, 1964, Ser. No. 339,738 6 Claims. (Cl. 198-134) The present invention relates to apparatus for drying coated sheet stock, and more particularly to such apparatus adapted for association with a screen stencil printing machine for drying coated sheet stock coated thereby.

The primary objects of the invention are to provide coated sheet drying apparatus which is especially well adapted for drying coated sheets delivered to the apparatus from a screen stencil machine; to provide apparatus for drying sheet stock which is coated with either quick-drying or slow-drying materials; to provide such drying apparatus which includes an endless wicket-type conveyor for drying sheets which are coated with slowdrying material, and in which the coated sheets are advanced from a receiving station across an upper reach of the wicket conveyor to a transfer station, and then returned across a lower reach of the conveyor to a delivery station; to provide means at the transfer station, where each sheet is transferred from its advance trip wicket carrier to the next preceding wicket carrier for the return trip, whereby the sheets are positively prevented from fall ing off the conveyor during the transfer; to provide similar means near the delivery station of the endless wicket conveyor for retaining the sheets on the conveyor; and in general to provide such coated sheet drying apparatus which is eflicient and versatile in performance, and also compact and reasonably economical in construction.

An illustrative embodiment of the invention is shown in the accompanying drawings, wherein:

FIGURE 1 is a side elevational view of the new coated sheet drying apparatus associated with a screen stencil printing machine shown somewhat diagrammatically at the left side of this view, the drying apparatus being here shown set up for drying sheet stock coated with slowdrying material on an endless wicket conveyor;

FIGURE 2 is a side elevational view of the same but with the drying apparatus set up for drying sheet stock coated with fast-drying material on an endless tape conveyor;

FIGURE 3 is a top plan view of the same;

FIGURE 4 is an enlarged, fragmentary, vertical sectional view of parts of the drying apparatus seen at the right side of FIGURES 1-3, the plane of section being indicated at lines 4-4 of FIGURES 3 and 6;

FIGURE 5 is an end elevational view of the same;

FIGURE 6 is a top plan view of the same;

FIGURE 7 is a further enlarged, fragmentary, vertical sectional view of parts of the machine seen at the lower right in FIGURE 4;

FIGURE 8 is an enlarged, fragmentary, vertical sectional view of parts of the drying apparatus, the plane of section being indicated at lines 8-8 of FIGURES 3 and FIGURE 9 is a top plan view of the same; and

FIGURE 10 is a vertical sectional view thereof taken on line 1010 of FIGURE 8.

Referring now in detail to these drawings wherein like parts are designated by the same numerals in the several views, the new coated sheet drying apparatus there shown comprises a system of three conveyors: an endless tape shunt conveyor generally designated 12; an upper, endless, wicket-type drying conveyor generally designated 13; and a lower, endless, tape drying conveyor generally designated 14. The upper and lower drying conveyors 13 and ice 14 are mounted on a framework comprising spaced upright posts 15 mounted by any suitable means on the floor.

The shunt conveyor 12, which is of downwardly opening obtuse angular form, has one end thereofthe left end as viewed in FIGURES 1-3, 8 and 9-mounted for pivotal movement about a horizontal axis at the delivery end of the screen stencil printing press generally designated 16. The shunt conveyor 12 is supported in the middle by a vertically adjustable standard comprising a lower tubular part 17 pivotally mounted on the floor, an upper part it; telescoping with the lower part 17, and on operating crank 19 by means of which the standar s upper part 18 can be raised and lowered and the shunt conveyor thus be raised and lowered about its pivotal connection to the printing press 16. These parts are all shown more or less diagrammatically in FIGURES 1, 2 and 8. The shunt conveyor comprises horizontally spaced, endless conveyor tapes 20 which pass around rollers 21, 22 and 23 mounted on the conveyors framework 24 (see FIGURES 8 and 9). Other endless tapes pass around the rollers 23 and rollers 26 mounted on the ends of horizontally spaced arms 27 at the delivery end of the shunt conveyor. Conventional means (not shown) are provided for driving the rollers and tapes so as to convey coated sheets 30 from the delivery end of the printing press to the receiving ends of the drying conveyors.

The upper, endless, wicket drying conveyor 13 comprises endiess sprocket chains 31 which pass around sprocket wheels 32 at the receiving end of the wicket conveyor (see FIGURE 8) and around other sprocket wheels 33 at the opposite or transfer end of the wicket conveyor (see FIGURE 4). Outwardly projecting, wicket-type sheet carriers 34 are mounted on the sprocket chains 31. Conventional means (not shown) are provided for driving the sprocket wheeis and chains so as to advance the sheet carriers 34 from the receiving station of this conveyor, seen in FIGURE 8, to the transfer station of the conveyor, seen in FIGURE 4, and to return the carriers 34 from the transfer station to the delivery station, also seen in FIGURE 8.

Each sheet carrier 34 comprises a plurality of horizontally spaced wire wickets and each wicket has a lip 35 on its outer end for supporting a coated sheet 30 thereon during the sheets return travel on the lower reach of the conveyor. The carriers are rigidly afiixed to the endless sprocket chain or conveyor 31 in such a manner that the angle between a specified carrier and the plane containing the segment of the sprocket chain to which a specified carrier is attached remains sub stantially constant throughout the path traveled by the endless conveyor. The sheet carriers 34 traverse the upper reach of the wicket conveyor in an upwardly and rearwardly extending position and traverse the lower reach of the conveyor in a downwardly and rearwardly extending position. At the transfer station seen in FIGURE 4 each stock sheet 30 falls from its advancing sheet carrier onto the next preceding carrier for its return trip.

Up to this point the description is of a :more-or-less conventional wicket-type drying conveyor. In such a conventional conveyor, many of the coated sheets would fall off the conveyor at the transfer station and inasmuch as these sheets were not yet completely dry they were spoiled. In the present invention means are provided for positively maintaining the sheets on the conveyor at the transfer station. These means comprise a plurality of endless tapes 36 (see FIGURES 4-7) which pass around rollers 37, 38 and 39 mounted on the frame of the apparatus. These tapes are so mounted at the transfer station as to be engaged by the outer ends of the sheet carriers 34 and driven thereby so as to maintain the coated sheets on the conveyor during their fall from one carrier to the next preceding carrier.

Other means are provided at the transfer station for insuring that each coated sheet is correctly positioned on its return trip carrier and supported on said carriers lip 35. These means comprise a pair of cylindrically formed brushes 40 mounted adjacent the endless tapes 36 for rotation about a horizontal axis. As shown, the brushes 40 are mounted on a shaft 43l which is driven by belts 42 passing around the roller 39 and around pulleys 43 on the shaft 41. The peripheries of the brushes 40 are adapted to contact the outer edge of each sheet so as to kick the sheet forwardly-upwardly onto the return carriers lip 35. FIGURE 7 illustrates in broken lines a coated sheet 30 which in its fall from its advance trip carrier missed the return trip carriers lip 35 but is still maintained on the conveyor by the tapes 36. In full lines in this view is illustrated the same sheet 3% after it has been kicked forwardly and upwardly beyond the lip 35, and in dotted lines the sheet is shown after it has come to rest with the carriers lip 35 supporting it in correct position for the return trip.

Means similar to the tapes 36 are provided at the wicket conveyors delivery station seen in FIGURES 1 and 8. As each sheet approaches the conveyors delivery station it falls from its return trip carrier 34 onto the next succeeding carrier, during which fall the sheet is maintained on the conveyor by endless tapes 44 which pass around rollers 45, 46 and 47 and which tapes are driven by the outer ends of the carriers 34. As each sheet 30 passes upwardly beyond the endless tapes 44, it slides by gravity off its carrier and onto a suitable receiving pallet 48 (see FIGURE 1) which may desirably be of the type which automatically lowers as the pile of dried sheets thereon increases in depth.

The lower endless tape drying conveyor 14 is of moreor-less conventional type, and comprises spaced endless tapes 50 which pass around rollers 51 and 52 mounted for rotation about horizontal axes, on the frame of the apparatus.

Operation The new coated sheet drying apparatus is equipped for drying sheet stock which is coated with either quick drying or slow-drying coating materials.

When drying sheets coated with quick-drying material, the shunt conveyor 12 is swung to its lowered position seen in full lines in FIGURE 2 and indicated in broken lines in FIGURE 8. Coated sheets 30 are conveyed by the shunt conveyor from the delivery end of the printing press 16 to the receiving end of the lower, endless tape drying conveyor 14 from which the sheets are delivered in dried condition onto a suitable pallet (not shown) at the left hand side of the machine as viewed in FIGURE 2.

When drying sheets coated with slow-drying material, the shunt conveyor 12 is moved to its elevated position seen in full lines in FIGURES l and 6. The coated sheets 30 are then conveyed by the shunt conveyor to the upper endless wicket-type drying conveyor 13. The wire wickets of each sheet carrier 34 pass between the spaced arms 27 and conveyor tapes 25 of the shunt conveyor, picking up a coated sheet 30 and advancing it to the right as seen in the drawings across the upper reach of the conveyor. This upper reach of the wicket conveyor, as shown, passes through a heated enclosure 53. When each coated sheet 30 arrives at the transfer station seen in FIGURE 4, it falls from its advance trip carrier 34 onto the next preceding carrier for the return trip. During this transfer, the sheets are prevented from falling off the conveyor by the endless tapes 36 which are driven by the outer ends of the sheets carriers themselves. After the transfer of each sheet from one carrier to the next preceding carrier, the sheet is kicked forwardly and upwardly by the rotating brushes 40 to insure that it is in correct position resting on the carriers lip 35 for the return trip across the lower reach of the conveyor.

As each sheet 38 approaches the delivery station of the wicket conveyor (see FIGURE 8) it falls from its return trip carrier 34 onto the next succeeding carrier 34. During this fall the sheets are prevented from falling off the conveyor by the endless tapes 44 which are likewise driven by the outer ends of the sheet carriers themselves. As the dried sheets 30 pass upwardly beyond the tapes 44, they slide by gravity off their carriers 34 and onto a suitable receiving pallet 48 as seen in FIGURE 1.

It will thus be seen that the invention provides a novel and efficient apparatus for drying sheet stock which is coated with either quick-drying or slow-drying coating material, and while but one specific embodiment of the invention has been herein shown and described, it will be understood that numerous details thereof may be altered or omitted without departing from the spirit of the invention as defined by the following claims.

I claim:

1. An endless conveyor for drying coated sheet stock, comprising:

means for driving said conveyor so that its upper reach advances from a receiving station to a transfer station while its lower reach returns from the transfer station to a delivery station;

a plurality of outwardly projecting sheet carriers mounted on said conveyor, each of said carriers having means for supporting coated sheets during the conveyors advance trip and other means for supporting coated sheets during the conveyors return trip, said carriers being rigidly affixed to said conveyor in such a manner that the angle between a specified carrier and the plane containing that segment of the conveyor to which said specified carrier is attached remains substantially constant throughout the traverse of said conveyor, whereby as each sheet arrives at the transfer station it falls from one carrier onto the next preceding carrier for the return trip such that said sheets are contacted by said carriers on the opposite side during the return trip from the side on which they were contacted by said carriers during the advance trip;

an endless tape means mounted at said transfer station on guide means so as to be simultaneously engaged by and span the ends of at least two adjacent carriers during the period in which a sheet is falling between them; and

means for moving said tape means in endless fashion at a lineal speed equivalent to the lineal speed at which the ends of said simultaneously engaging carriers are traveling whereby the coated sheets are retained on said conveyor during their fall from one carrier to the next preceding carrier at said transfer station.

2. An endless conveyor for drying coated sheet stock according to claim 1 in which the outwardly projecting sheet carriers are of the wicket type.

3. The apparatus as set forth in claim 1 which further comprises means for insuring that each coated sheet is correctly positioned on its return trip carrier and supported on said carriers lip comprises a cylindrically formed brush mounted adjacent the endless tape at the transfer station for rotation about a horizontal axis, the periphery of said brush being adapted to contact the outer edge of each sheet so as to kick the sheet forwardly-upwardly onto the return trip carriers supporting means.

4. An endless conveyor for drying coated sheet stock, comprising:

means for driving said conveyor so that its upper reach advances from a receiving station to a transfer station while its lower reach returns from the transfer station to a delivery station;

a plurality of outwardly projecting sheet carriers mounted on said conveyor, each of said carriers having sesame means for supporting coated sheets during the conveyors advance trip and other means for supporting coated sheets during the conveyors return trip, said carriers being rigidly afiixed to said conveyor in such a manner that the angle between a specified carrier and the plane containing that segment of the conveyor to which said specified carrier is attached remains substantially constant throughout the traverse of said conveyor, whereby as each sheet approaches the delivery station it falls from one carrier onto the next succeeding carrier for delivery therefrom such that after said fall each said sheet is contacted by said succeeding carrier on the side opposite from that side on which it was contacted by said one carrier; and

an endless tape means mounted at said delivery station on guide means so as to be simultaneously engaged by and span the ends of at least two adjacent carriers during the period in which a sheet is falling between them, said tape being driven in endless fashion by said carriers engaged therewith at a lineal speed equivalent to the lineal speed of the outer ends of said engaged carriers whereby the coated sheets are retained on said conveyor during their fall from said one carrier to said next succeeding carriers at said delivery station.

said carriers being rigidly affixed to said conveyor in such a manner that the angle between a specified carrier and the plane containing that segment of the conveyor to which said specified carrier is attached remains substantially constant throughout the traverse of said conveyor, whereby as each sheet arrives at the transfer station it falls from one carrier onto the next preceding carrier for the return trip;

an endless tape so mounted at the transfer station as a cylindrically formed brush mounted adjacent the end less tape at the transfer station for rotation about a horizontal axis, the periphery of said brush being adapted to contact the outer edge of said sheet so as to kick the sheet forwardly-upwardly onto the return trip carriers lip.

5. An endless conveyor for drying coated sheet stock according to claim 4 in which the outwardly projecting sheet carriers are of the Wicket type.

References (Iited by the Examiner UNITED STATES PATENTS 6. An endless conveyor for drying coated sheet stock 499%160 6/1893 P P comprising; 3 0 9/1911 Klflg 198*84 means for driving said conveyor so that its upper reach 1,184,648 5/1916 Horton advances from a receiving station to a transfer sta- 1,463,181 9/1923 Wagner 198-34 tion while its lower reach returns from the transfer 5 5 11/ 1925 m l 198-134 station to a delivery station; 2,0 2,720 5/ 1935 Smith 198-134 a plurality of outwardly projecting sheet carriers pro- 2,883,033 4/1959 Armstrong.

vided with lips on the outer ends thereof which extend rearwardly-upwardly during the conveyors return trip for supporting coated sheets during the conveyors return trip and other means for supporting coated sheets during the conveyors advance trip,

EVGN C. BLUNK, Primary Examiner.

4O WILLIAM B. LABORDE, Examiner.

R. E. AEGERTER, Assistant Examiner. 

1. AND ENDLESS CONVEYOR FOR DRYING COATED SHEET STOCK, COMPRISING: MEANS FOR DRIVING SAID CONVEYOR SO THAT ITS UPPER REACH ADVANCES FROM A RECEIVING STATION TO A TRANSFER STATION WHILE ITS LOWER REACH RETURNS FROM THE TRANSFER STATION TO A DELIVERY STATION; A PLURALITY OF OUTWARDLY PROJECTING SHEET CARRIERS MOUNTED ON SAID CONVEYOR, EACH OF SAID CARRIERS HAVING MEANS FOR SUPPORTING COATED SHEETS DURING THE CONVEYOR''S ADVANCE TRIP AND OTHER MEANS FOR SUPPORTING COATED SHEETS DURING THE CONVEYOR''S RETURN TRIP, SAID CARRIERS BEING RIGIDLY AFFIXED TO SAID CONVEYOR IN SUCH A MANNER THAT THE ANGLE BETWEEN A SPECIFIED CARRIER AND THE PLANE CONTAINING THAT SEGMENT OF THE CONVEYOR TO WHICH SAID SPECIFIED CARRIER IS ATTACHED REMAINS SUBSTANTIALLY CONSTANT THROUGHOUT THE TRAVERSE OF SAID CONVEYOR, WHEREBY AS EACH SHEET ARRIVES AT THE TRANSFER STATION IT FALLS FROM ONE CARRIER ONTO THE NEXT PRECEDING CARRIER FOR THE RETURN TRIP SUCH THAT SAID SHEETS ARE CONTACTED BY SAID CARRIERS ON THE OPPOSITE SIDE DURING THE RETURN TRIP FROM THE SIDE ON WHICH THEY WERE CONTACTED BY SAID CARRIERS DURING THE ADVANCE TRIP; AN ENDLESS TAPE MEANS MOUNTED AT SAID TRANSFER STATION ON GUIDE MEANS SO AS TO BE SIMULTANEOUSLY ENGAGED BY AND SPAN THE ENDS OF AT LEAST TWO ADJACENT CARRIERS DURING THE PERIOD IN WHICH A SHEET IS FALLING BETWEEN THEM; AND MEANS FOR MOVING SAID TAPE MEANS IN ENDLESS FASHION AT A LINEAL SPEED EQUIVALENT TO THE LINEAL SPEED AT WHICH THE ENDS OF SAID SIMULTANEOUSLY ENGAGING CARRIERS ARE TRAVELING WHEREBY THE COATED SHEETS ARE RETAINED ON SAID CONVEYOR DURING THEIR FALL FROM ONE CARRIER TO THE NEXT PRECEEDING CARRIER AT SAID TRANSFER STATION. 